X-ray inspection systems using X-rays have been known as systems for inspecting the internal state of a measurement object non-destructively. The X-ray inspection system irradiates an X-ray, which is output being diverged from one point of the X-ray source in a predetermined angle direction, onto the measurement object, and capturing the image of the X-ray which transmitted through the measurement object using an X-ray image capturing unit, so as to inspect the internal status of the measurement object.
Japanese Patent Laid-Open No. 11-108858 discloses an X-ray inspection system which inspects a plurality of measurement objects which move on a line, such as a belt conveyor, one after another, using the above mentioned X-ray inspection system. An object of this X-ray inspection system is to obtain a clear X-ray fluoroscopic image while capturing the X-ray image of the moving measurement object. In other words, when the measurement object passes on a line between the X-ray source and X-ray image capturing unit, a gate signal is sent to the X-ray image capturing unit, operation of the X-ray image capturing unit is controlled by this gate signal, and an X-ray fluoroscopic image is captured at the moment when the measurement object crosses between the X-ray source and X-ray image capturing unit.